The present invention relates to the utilization of the exhaust heat from a household clothes dryer or other appliance which provides an exhaust of warm moist air. The recovered heat may be used directly to heat a specific area of the house or in the case of a house having a forced air heating system, be introduced into the plenum of the furnace by way of the cool air return duct.
Generally, the excess heat generated by clothes dryers and like appliances is exhausted to the outside atmosphere, and thus wasted as a possible supplementary home heating source. Since the amount of heat recovered from a clothes dryer would be small compared to the overall heat requirement for a home during a heating season, a heat recovery device must be simple and easy to install in order to be economically justified.
The high moisture content of dryer exhaust air renders it undesirable for direct heating uses; however, a device comprising any of the commonly used condensers is likely to be too expensive to be commercially viable. While the recovered warm air does not have to be completely dry, a sufficient amount of moisture must be removed so that introduction of the recovered warm air into the house will not result in condensation, or undesirable fluctuations in the humidity of the interior atmosphere.
In addition to using the dried exhaust air directly for home heating, it would also be desirable to provide a device which introduces recovered warm air into a heat exchange relationship with the hot dryer exhaust thus further warming the recovered air prior to its use as a heating source.
Since the exhaust heat from the clothes dryer may not always be needed, means should be provided in a heat recover device to allow the exhaust alternatively to pass directly to the outside atmosphere.